Two new α-pyrone derivatives from the marine-derived Streptomyces sp. SYPHU 0003

Four α-pyrone derivatives (1–4) were isolated from marine-derived Streptomyces sp. SYPHU 0003, among which two new compounds (1 and 2). The structures and absolute configurations of compounds 1–4 were established by comprehensive spectroscopic analyses (MS and NMR), combined with ECD calculations and modified Mosher′s method. Antibacterial activity revealed that compounds 1–4 exhibited identical activity against Acinetobacter baumannii with the MIC values of 64 μg mL−1.